Lenses—optical devices that transmit and refract light—or arrays of lenses, may be fabricated on the back of a semiconductor laser substrate for back emitting VCSEL (Vertical Cavity Surface Emitting Lasers) or VECSELs VCSEL (Vertical (Extended or External) Cavity Surface Emitting Lasers) designs. A VCSEL is a type of semiconductor laser diode with laser beam emission perpendicular from the top surface. In contrast, conventional edge-emitting semiconductor lasers emit from surfaces formed by cleaving the individual chip out of a wafer. VECSELs then are a type of VCSELs that have been reconfigured to have the cavity extended outside of the wafer. In an alternative approach, the lens array may be fabricated separately, in a different material, such as glass or transparent polymer. The lens array may be configured to align, by mechanical means, to the lasers in an assembly or manufacturing process. Such fabrication of the lens arrays may generally be performed by transferring a pattern from photoresist into the surface of the substrate by etching. An etched lens may be characterized by its respective curvature or Radius of Curvature (ROC), and this curvature may be a significant aspect of the performance of the lens. An etched lens may also be a Fresnel or diffractive structure where the light is controlled by a pattern that produces a similar phase delay of the light as a conventional lens. In that case, a pattern from photoresist (or an electron beam resist, or a resist patterned by physical imprinting, or stamping) may also be transferred into the surface of the substrate material by etching.